The N-way power combiner/divider according to the invention is a solution to high power coaxial combining or dividing. This new design has many improvements over other combining techniques. The invention is based on a circuit design by Ulrich H. Gysel of the Stanford Research Institute and was presented to the IEEE in 1975. Ulrich H. Gysel, A New N-Way Power Divider/Combiner Suitable for High Power Applications, IEEE-MTTS-5, International Symposium Digest, pg. 116, 1975. The Gysel design, referred to as a Gysel Network, is, in turn, an improvement to the N-Way combiner/divider devised by Wilkinson. E. J. Wilkinson, An N-Way Hybrid Power Divider, IRE Trans. on Microwave Theory and Techniques, Vol. MTT-8, pp. 116-118 (January 1960). The improvements made by Gysel include: external isolation loads, easily realizable geometry and monitoring capabilities at the input ports. The original Wilkinson design was only applied to strip line systems. Years later, Harris Allied Broadcast Division incorporated the Gysel Network to a coaxial application in their Platinum.TM. Series FM Transmitter (trade mark of Harris Corporation). This solid state modular transmitter combined power modules to form a 10 kW output using the Gysel Network.
While the Gysel network is conceptually simple, implementing efficient high power combiners with coaxial transmission lines has remained difficult. Lower power systems, on the other hand, have been implemented using strip-line techniques and employing planar substrates. These techniques, however, are somewhat difficult to apply to high power load levels.
U.S. Pat. No. 3,904,990, expressly incorporated herein by reference, provides an N-way power divider with remote isolating resistors. U.S. Pat. No. 4,365,215, expressly incorporated herein by reference, provides a high power coaxial power divider. U.S. Pat. No. 4,369,415, expressly incorporated herein by reference, provides a coaxial transmission power line divider. U.S. Pat. No. 4,656,434, expressly incorporated herein by reference, provides an RF power amplifier with load mismatch compensation. U.S. Pat. No. 4,875,024, expressly incorporated herein by reference, provides a low loss power splitter. U.S. Pat. No. 5,111,166, expressly incorporated herein by reference, provides an N-way power combiner having N reject loads and a common heat sink. U.S. Pat. No. 5,164,689, expressly incorporated herein by reference, provides an N-way power combiner/divider. U.S. Pat. No. 5,206,604, expressly incorporated herein by reference, provides a broadband high power amplifier having an N-way power combiner. U.S. Pat. No. 5,410,281, expressly incorporated herein by reference, provides a microwave high power combiner/divider. U.S. Pat. No. 5,543,762, expressly incorporated herein by reference, provides an N-way impedance transforming power divider/combiner.
The following patents are related to the present invention, and are each expressly incorporated herein by reference: U.S. Pat. Nos. 3,747,026; 4,092,616; 4,163,955; 4,254,386; 4,263,559; 4,263,568; 4,328,471; 4,335,347; 4,401,955; 4,463,326; 4,543,545; 4,553,266; 4,590,446; 4,644,301; 4,652,880; 4,684,874; 4,693,694; 4,769,618; 4,835,496; 4,916,410; 4,926,145; 5,017,886; 5,021,755; 5,055,798; 5,079,527; 5,083,094; 5,121,084; 5,136,256; 5,150,084; 5,187,447; 5,206,611; 5,223,809; 5,256,987; 5,283,540; 5,304,943; 5,313,174; 5,329,248; 5,389,890; 5,445,546; 5,543,751; 5,561,395; and 5,576,671.